Goffin’s cockatoos excel at basic weight sorting but struggle with more complex tasks requiring associating heavier/lighter ...

The American Journal of Psychology, Vol. 95, No. 4 (Winter, 1982), pp. 571-580 (10 pages) Pigeons learned a pair of two-choice conditional discriminations concurrently. One was red/green identity ...

Biases in judgement of ambiguous stimuli, as measured in a judgement bias task, have been proposed as a measure of the valence of affective states in animals. We recently suggested a list of criteria ...